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Complete Lethal Weapon 3

Carl Spiby

Carl Spiby

Registered
Joined
Feb 24, 2013
Messages
2,707
Location
Kendal, Cumbria
It finally arrived yesterday evening! Pretty happy with it, it was sold with a non-working display, but after poking around with a multimeter and deciding the voltages were infact there, I found a ribbon cable that wasn't plugged in to the DMD controller. @Sonny_Jim how did you miss that?! :p

I've given it a quick wipe (so I suppose its a minter now) and tried playing a game on it, but I'm suffering resets, 5v test point shows 4.8v, is that high enough? I don't see any fluctuation on my meter when it resets but maybe its too quick for it to catch it. I have a couple of theories at the moment, maybe a diode on the flipper coil or a stuck EOS, will have to check it out soon.

Many metal parts are rusty on this machine due to it living in a shed by the sea for many years, if I don't own a buffer or a tumbler, what is the best way to shine them back up? Scotchbrite? Or is that only for tarnished rather than rusty metal?

On with the pictures:

dl.dropboxusercontent.com_u_29769115_Lethal_20Weapon_20Shop_IMG_20140210_220754.jpg

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dl.dropboxusercontent.com_u_29769115_Lethal_20Weapon_20Shop_IMG_20140210_220735.jpg

dl.dropboxusercontent.com_u_29769115_Lethal_20Weapon_20Shop_IMG_20140210_220718.jpg

dl.dropboxusercontent.com_u_29769115_Lethal_20Weapon_20Shop_IMG_20140210_220701.jpg

dl.dropboxusercontent.com_u_29769115_Lethal_20Weapon_20Shop_IMG_20140210_220637.jpg

dl.dropboxusercontent.com_u_29769115_Lethal_20Weapon_20Shop_IMG_20140210_220618.jpg
 
Nice bit of luck with the dmd, this was the first dmd pin I owned too, great fun
 
Any rust on chrome can be removed with aluminium foil and a bit of water..
 
On the re-sets - have you tried reseating ALL the connectors from the CPU board to the main driver board yet?
 
Paul R Owen said:
On the re-sets - have you tried reseating ALL the connectors from the CPU board to the main driver board yet?
Click to expand...
After reading GrizZ's link I need to reseat CN6 then check the 5V at either end. Resets do appear to be related to the right flipper though.

Work is getting in the way of my fun :(
 
Looking good Carl, a relief the DMD worked I bet. I wonder how many miles it did circling the country in Martins van? :rolleyes:
 
What Wizcat said, bargain with new board and working dmd.

Reckon once you've shopped this machine,which should be quite a simple task, you'll have 1 sweet machine. As I've said before, was my 1st and you never forget your first :rolleyes:

Si
 
Nice one mate.

As far as voltage goes, anything below 4.9 is a cause for concern as far as my reading on the subject goes. Try sliding power connectors up and down their pins to clear any crud off and re-seat them firmly to see if that makes any difference.

My FT resets seem to have been due to a voltage drop between the power and CPU boards. Most resets were due to the flippers drawing too much power when hit together.
 
I found a ribbon cable that wasn't plugged in to the DMD controller. @Sonny_Jim how did you miss that?!
Click to expand...
I didn't, I had deliberately left it unplugged as I didn't think it would be a good idea to power the DMD when the -110V was missing. I'm mystified why it's suddenly started working as it definitely was missing the high voltage. For once being bounced around in the back of a van has done it good!

Regarding the resets, I would replace CN17 plug on the CPU board, it's fairly crispy and there's quite a bit of voltage drop between the CPU and PSU.
 
Just been tinkering trying to solve this resetting lark, didn't see the reply about CN17 until just now but its getting a good 4.8-4.9v on the 5v line, there's maybe 0.05v drop between the PSU and CPU. But it will without fail reset when both flippers are pressed.
 
On the power supply check and replace if necessary the 4x3 connector. Also replace the 100uF 25v capacitor, which often leaks. 4.8v I'd too low.
 
There's couple of hacks and broken trace repairs on the PSU, I will inspect the 4x3 connector another day, the caps look pretty new, I believe @Sonny_Jim rebuilt the 5/12v on it.

Sperodically the middle trough switch will stop working, I was about to check continuity and it started working again,no loose wires and the diode is present.

Time to relax with some TV now.
 
Ordered replacement caps anyway seeing as they're only a few quid, going to try and get the TN5 from somewhere too.

Meanwhile, the PSU looks like this.

2014-02-11 22.53.32.jpg

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First go at soldering tonight, removed all the components in preparation for the new ones, they had been previously replaced but for the pence it costs to replace them, I might as well.

I have a replacement bipolar transistor coming from Andy, hopefully this will solve the 5V problem if it doesn't the only thing left to replace is the LM723, then I can move on to stripping the playfield.

Tried to do it as cleanly as I could using a combination of de-soldering braid and a solder sucker, this is where it stands now.

102_0723.JPG
 
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I've replaced C3, C2, C1 and DB1 and I now have 4.95v on TP1. I haven't replaced TR5 yet as it hasn't arrived.

I'm trying to test ripple but I'm not sure I'm doing it right, on my DMM I set 200v on the A/C scale it's coming out as 10v, I'm guessing that's pretty terrible?

The machine is still resetting when both flippers are spammed and it can actually get itself in to a state where the blanking light goes out, the music/dmd is still running but no coils or buttons work :confused:

Edit: testing for incoming a/c at F1 and F2 on the PSU I find one is 9.9vac and the other is barely managing 8.9vac, now I'm pretty sure these are both meant to be 9vac and they are when measured at the connector when its unplugged.

Could crap fuse holders be the cause? Starting to run out of ideas.
 
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DE PSUs are prone to crap fuse holders, but generally they're pretty obvious. Give the fuses a push, and if the fuse holder breaks off or is already missing a piece, replace it. Also check that you have good diodes on the flipper coils, and no corrosion to the chip sockets on the CPU.
 
Thanks Andy, I think next logical step is going to be fuse holders.

I managed to borrow an oscilloscope to measure ripple, its only just over 10mvac so I don't think the +5v is a problem now. I really want to get to the bottom of why F1 fuse is heating up so much, you can barely touch it so it must be pulling a hell of a lot of current whatever it is. I checked the components on the other boards but nothing is hot.

All kinds of random things are going on, sometimes flippers stop then outhole coil won't fire and switch matrix goes 'dicky' another time the whole machine resets. I have never observed a dip in +5v when the machine cuts out though.

:confused::(o_O
 
Are the connectors dirty/have corrosion on them ? Make sure all connectors are nice and clean and free from crap.
 
Connectors pins are clean, but I think the connectors could do with redoing if only for piece of mind.

As a test tonight I pulled all the connectors out the PSU except CN1, CN2 and CN9 and turned it on for 10 minutes, the fuses were cold to the touch.

I then plugged in CN6 which caused one of the 2 fuses to get a little warm and drop 1vac across it. The LM732 appears to be operating correctly.

CN6 appears to supply +5v -12v and +12v does this just go to the MPU and the sound board?
 
Now managed to get MPU board up to 4.9vdc but the reset issue is as bad as ever :(

Anyone got any suggestions on what to try next?
 
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